1. Technical Field
The present disclosure generally relates to well bore tools and in particular to methods and apparatus for downhole sample evaluations.
2. Background Information
Oil and gas wells have been drilled at depths ranging from a few thousand feet to as deep as five miles. Information about the subterranean formations traversed by the borehole may be obtained by any number of techniques. Techniques used to obtain formation information include obtaining one or more formation fluid samples and/or core samples of the subterranean formations, for example. These samplings are collectively referred to herein as formation sampling.
Modern fluid sampling includes various downhole tests and sometimes fluid samples are retrieved for surface laboratory testing. It is often desirable to evaluate fluids in the downhole environment to estimate various characteristics and properties of the fluids. Downhole evaluations where the fluid under investigation remains substantially at downhole conditions increases efficiency of the operation by reducing or eliminating the need to remove the evaluation tool and/or fluid sample from the borehole and provide more accurate estimates by maintaining the fluid at substantially downhole conditions.
The downhole conditions, such as temperature and pressure, are greater than conditions at the surface. The increase in temperature and/or pressure, for example, can reduce the accuracy of downhole testing tools, such as detectors, which can result in inaccurate downhole sample property measurements. There is a need, therefore, for improved apparatus and methods for downhole sample property estimations.